Department of Fruit-Growing, Faculty of Viticulture and Horticulture, Agricultural University Plovdiv, 12 Mendeleev, 4000 Plovdiv, Bulgaria
Abstract. The growth and reproductive characteristics of the apple variety Braeburn 7926 grafted on two rootstocks with different growth potential – M9 Pajam2 and MM106 is studied. Both rootstocks induce growth manifestations on the variety which are in compliance with their commonly accepted characteristics in fruit growing – proven higher values of the cross – section area of the stem, as well as, in respect to the volume of the crown of the grafted variety are recorded in a combination with the semi – weakly growing rootstock MM106 in comparison to the weakly – growing M9 Pajam2. The combination Braeburn 7926/M9 Pajam2 is more productive during the first year of the observed period and this is due to the earlier fruitgrowing stage of the variety which is affected by the weakergrowing rootstock. The yields are slowly declining in the following years in comparison to the combination Braeburn 7926/MM106 because of the reflected smaller crowns volume affected by the weaker rootstock. The productivity coefficient shows higher values when rootstock M9 Pajam2 is used only during a part of the observed period. A higher planting density can be recommended when the weaker growing sort-rootstock combination is applied for a more rational usage of the vegetative area.